Replaceable-blade knives such as utility knives using trapezoidal blades, and carpet knives using rectangular blades, enable use of a comfortable and contoured gripping handle with replaceable blades appropriate to the material to be cut. Storage of replacement blades in a drop-down compartment positioned within the gripping handle is disclosed in U.S. Pat. Nos. 3,577,637, 3,593,417, and 3,927,473. These prior-art arrangements, however, are somewhat inconvenient to use, as multiple steps are required to release a dull blade for replacement, and to release the holder for access to a new blade.
The invention herein disclosed is directed to a knife of this general type, and in which a drop-down blade holder is unlatched and released by movement of a blade clamp to a position enabling removal of a dull blade, and immediate installation of a replacement blade.